diff --git a/launch/msckf_vio_tum.launch b/launch/msckf_vio_tum.launch
index 1d458d2..a28de3f 100644
--- a/launch/msckf_vio_tum.launch
+++ b/launch/msckf_vio_tum.launch
@@ -18,7 +18,7 @@
       output="screen">
 
       <!-- Photometry Flag-->
-      <param name="PHOTOMETRIC" value="false"/>
+      <param name="PHOTOMETRIC" value="true"/>
 
       <!-- Debugging Flaggs -->
       <param name="PrintImages" value="false"/>
diff --git a/src/msckf_vio.cpp b/src/msckf_vio.cpp
index d56d1a9..16a5951 100644
--- a/src/msckf_vio.cpp
+++ b/src/msckf_vio.cpp
@@ -1314,8 +1314,8 @@ void MsckfVio::PhotometricMeasurementJacobian(
     // frame derivative calculated convoluting with kernel [-1, 0, 1]
     dx = feature.PixelIrradiance(cv::Point2f(p_in_anchor.x+1, p_in_anchor.y), anchor_frame) - feature.PixelIrradiance(cv::Point2f(p_in_anchor.x-1, p_in_anchor.y), anchor_frame);
     dy = feature.PixelIrradiance(cv::Point2f(p_in_anchor.x, p_in_anchor.y+1), anchor_frame) - feature.PixelIrradiance(cv::Point2f(p_in_anchor.x, p_in_anchor.y-1), anchor_frame);
-    dI_dhj(0, 0) = dx/pixelDistance.x;
-    dI_dhj(0, 1) = dy/pixelDistance.y;
+    dI_dhj(0, 0) = dx/(pixelDistance.x*N*N);
+    dI_dhj(0, 1) = dy/(pixelDistance.y*N*N);
 
     gradientVector.x += dx;
     gradientVector.y += dy;